The present invention relates to a method for manufacturing a weather strip which is attached to a vehicle body panel or a door panel with which a door glass pane in a motor vehicle is brought into contact, and more particularly to a method for manufacturing a weather strip, in which a protective film having a low friction characteristic and an increased tightness is integrally extruded with the weather strip body.
Conventionally, the known method for manufacturing this type of weather strip for motor vehicles comprises the step of forming an abutment portion, with which the glass pane may enter into contact, from a synthetic rubber or a thermal plastic elastomer having a flexibility, a resiliency and a low friction characteristic so as to retain a water-tightness, and so as to make smooth an opening and closing movement of the glass pane. However, in this weather strip manufacturing method, such synthetic rubber or thermal plastic elastomer for forming the abutment portion has a problem in that it may be susceptible to damage if it is subject to a slight rubbing action, and its skin may be easily toughened and torn off upon being contacted by a solvent such as a white gasoline.
Another manufacturing method of the weather strip is also known, wherein the method comprises the step of melting a urethane resin or a nylon onto the abutment portion of the weather strip in order to prevent the weakening of a synthetic rubber or a thermal plastic elastomer to form the abutment portion of the weather strip. However, there has been a drawback in this weather strip manufacturing method that an increased frictional resistance may serve to prevent smooth opening and closing movements of the glass pane, and that the manufacturing process is expensive and cumbersome, since the steps of heating and melting the urethane resin and nylon must be carried out separately from the step of molding the weather strip body.
Furthermore, another weather strip manufacturing method is also known, wherein the method comprises the step of adhesively bonding a synthetic resin tape having molybdenum material with the abutment portion of the weather strip so as to improve the sliding characteristics of the latter. However, in this weather strip manufacturing method, the step of adhesively bonding the tape over the abutment portion is not only very difficult and cumbersome to carry out, but it also causes a problem in that the synthetic tape may not be adhesively bonded with sufficient strength over non-flat portions such as curved and corner areas of the weather strip.